In recent years a great deal of interest has been shown in the provision of electrochromic displays having, for example, a digital or analog readout such as in commonly assigned U.S. Pat. No. 3,908,355 issued Sept. 30, 1975 in the name of Leo Wiesner and U.S. Pat. No. 3,987,433 issued Oct. 19, 1976 in the name of Richard Howard Kennedy.
Other prior art patents of interest include U.S. Pat. No. 3,932,860 issued Jan. 13, 1976 to Sam G. Cohen, U.S. Pat. No. 3,881,311 issued May 6, 1975 to Tetsuro Hama et al, U.S. Pat. No. 3,797,225 issued Mar. 19, 1974 to Tetsuro Hama et al, U.S. Pat. No. 3,949,242 issued Apr. 6, 1976 to Masataka Hirasawa et al, U.S. Pat. No. 3,807,832 issued Apr. 30, 1974 to George Augustus Castellion and U.S. Pat. No. 3,839,857 issued Oct. 8, 1974 to Donald Joseph Berets et al. These prior art patents are merely typical of the art showing passive electrooptic display devices and other pertinent references may exist.
From the prior art, it is known to write a selected segment(s) by applying a (single) write voltage potential (usually having a negative polarity) with respect to a common electrode for a period to completely write the selected segment(s) and then either removing the write potential from the written segment(s) or continuously applying the write potential to the written segment(s).